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St Andrews debate

John Shade, of Climate Lessons blog, sends this report on my debate at St Andrews.

On a wet and windy day, off to St Andrews, where the School of Geography and Geosciences was holding a discussion meeting on climate as one of its World Series Seminars. Speakers: Andrew Montford, and Tom Crowley, a recently retired professor of paleoclimatology. Chaired by Dr Robert Wilson, who said that he was a great believer in discussion where there was discord, and that there was discord in the climate world. He gave Andrew a pleasant and welcoming introduction, noting that he had been quoted in one newspaper report as believing that CO2, all things being equal, will make things warmer.

Before Andrew’s presentation Dr Wilson, tried a quick straw poll of the roughly 60 or 70 people present (my guess, and I also guess that most were undergraduate or graduate students). He asked who believed there had been global warming, and that man had contributed to it – which was a disappointing note since the crucial areas of debate are not on those beliefs, but on the magnitude and other details of climate change over the next 50 to 100 years or so. Then he asked who saw themselves as sceptical. I raised my hand both times, albeit a bit hesitantly the first time. Not many raised their hands the second time – a ‘few’ was how Robert described it.

Andrew’s topic was ‘The Global Warming Debate After Climategate’. He recapped the basic details of Climategate, and of the serious allegations that were raised about climate scientists as a result. He talked through each of the three enquiries and demonstrated that they were all inadequate and had failed to directly address the allegations, thereby earning Andrew’s epithet of ‘whitewashes’. He said people have noticed that these were not serious attempts to get at the truth, and this destroyed trust. He returned again to this theme of lost or damaged trust, noting the IPCC standing by the hockey stick plot even when it knew it was wrong, and of the sleight of graph involved in splicing instrumental readings on to a time series plots of reconstructed temperatures when the reconstructed values turned sharply down instead of up. He noted the curious amount, and direction, of adjustments to temperature records – always to make the present warmer and the past cooler. He did not know whether or not the adjustments were justified, but merely noted that they made him uneasy.

He maintained that trust needs to be rebuilt in climatology, noting that he did not believe all climatologists were corrupt, but that there were some bad eggs in there. He welcomed the willingness of some to discuss issues in a civilised way, and said that both sides need to work very hard to be nice to each other. As more recent development, he noted the facile claim of accelerating warming by doing successive straight-line fits to sections of the temperature record, showing the illustration (due to Paul Matthews) of how this worked in a similar way when done to a simple sine wave. Why did some talk of acceleration based on this?, he asked and noted it as an example of the sort of thing that has to stop. He recalled being told by one climatologist who had posted a 5* review of HSI on Amazon, that he had done so anonymously to avoid repercussions. Turning to recent global temperature reports, he noted that the lack of warming was catching the attention of such as Phil Jones, and of people he had met in the Met Office recently. He noted that climate models had not been working well at the global level, and at the regional level were even worse, and showed a plot contrasting predictions made through the IPCC in the year 2000 diverging up and away from the actuals which were fluctuating about an approximately horizontal trend (chart due to Lucia on the Blackboard blog). He asked if these such models were fit tools for government policy, and said he though not. In winding up, he reiterated that trust has been destroyed, and that the phrase ‘Trust Me, I’m a Scientist’ doesn’t hold water anymore.

Recently retired, Professor Tom Crowley was the other speaker, and his subject was ‘Progress in Understanding Climate of the Last Millenium’. He started by saying he was feeling as bit wrong-footed by Andrew’s talk being different from what he had expected, an observation he was to make again a couple of other times. I think he had been expecting Andrew to be talking mostly about the hockey stick plot.

His introductory slide was of a roadside sign for the ‘Chaos Café’, and this stayed up for quite a while until he got into his main materials. Before then, he invited us to be concerned about the recent high temperatures being reported in the States, with averages in March being 8.6F above normal. He said this was a colossal warming.

He spoke very highly of the IPCC reports, and returned several times to this later. He had used the 1st and 2nd assessment reports as core material for classes he had taught back then on climate. He said virtually nobody has disputed what they have said, and noted that some 50,000 comments on drafts have been responded to. He noted that government representatives had voted sentence by sentence on the Summary Reports.

He showed showed a new plot (not yet published) which had the hockey stick shape using tree rings from 1801 to 1984, constructed using simple averaging of the reconstructions used. He noted that while individual records may be flawed, this averaging helped produce a more reliable result. He talked to some of the major features on the earlier part of the plot, generally referring to volcanic eruptions as likely causes, and then later, from about 1900 onwards by aerosols due to industrial pollution. He showed a plot of sulphate depositions found in Greenland ice – in the flight path of the prevailing winds from the US. These showed a drop in the 1930s which he associated with the Depression of those years, a drop which was not recovered from on the plot until 1954, roughly following a similar performance in the Dow Jones Index. The Clean Air Act in the 1970s led to improvements, but before that there was a surge of readings from abour 30ppb to 200ppb at their peak. This he described as great wads of sulphur, having earlier asked any gardeners present if they would deliberately pack sulphuric acid powder around the base of their valued plants.

He showed another plot with global temperatures (mostly as per Hadcrut means as I recall) , with CO2 growth almost perfectly superimposed from about 1800 to the present, and once again invited our concern. A further, yet to published plot due to Levitus, showed substantial heating in the upper ocean. All this he described as rock solid.

He said the IPCC view was that doubling of CO2 would lead to global mean temperatures rises of 2 to 3C in 30 years from now, and these would be the highest in a very long time (I cannot decipher my notes on the actual time period). He repeated the assurance of the IPCC about continued warming, and his confidence in the IPCC.

My notes are a bit scrappy for the question and answer session which followed, and which was ably handled by Dr Wilson, since I was from time to time formulating questions or comments of my own.

An early question concerned differences in variability displayed on different sections of plots shown by Tom – described by the questioner as ‘huge differences in uncertainty’. Another questioner argued that a detailed re-analysis of tree-ring data was called for in general. The question of how much longer a period without warming would cause people to say something was wrong with the models and/or the claims of a warming threat. Tom suggested that if warming not resumed by 2020, that would cause concern. A questioner noted that there were massive leaps being made from projected temperature rises to talk about climate impact in general – impacts that have not been remotely justified e.g. talk of floods and droughts and famines and so on.

The excess winter deaths in Scotland were raised to illustrate more harm from cooling than warming here. An audience member claimed that climate scientists were intrinsically sceptical – that was part of science, and that it was very misleading to think of a simple divide between climate sceptics and true believers. The same person also praised peer review as one of the strengths of climate science, and urged sceptics to get engaged and try to get published. There was some mention of Arctic ice thinning, the high variability Arctic sea ice and thickness so that even a dramatic summer melt at the pole would not be unprecedented even in the last 100 years, of sub-tropical drought forecasts and poor guidance to the Australian government about permanent drought down there (with desalination plants build not long before floods due to very heavy rains appeared and the plants were mothballed).

The Clausius-Clapeyron relationship was raised to note airborne water vapour would increase with rising surface temperatures, and that led to questions about negative feedbacks involving clouds tending to counter such rises). Someone noted that economic models also needed a lot more examination. What should be done? Bets were bandied about about temperature rises in the near future. It was noted that the self-interest of developing states such as India and China may not coincide with greenhouse gas reduction. Tom said it would be in the self-interest of the States to reduce dependence on imported oil, and that in general people should try to do what benefits their own country. A questioner had asked if it seemed that global governance was the only way to go if greenhouse gas reductions were to be addressed.

The climategate scandal was mentioned, and Tom said that it had nto affected the science, and that anyway, scientists were human beings. He felt that if there was 1 dodgy paper out of 100, that one would be blown up out of all proportion by the blogosphere. A suggestion of massive oil funding by an audience member was greeted with derision by the ‘sceptics’ present, and when Tom started to talk of Exxon in particular, there was a remark from the audience to the effect that going down that line would make ‘us’ no better than the sceptics, and that produced an approving murmur in the audience and the topic was dropped. A questioner asked what would it take to change a sceptic’s mind – for example, if they saw there was only a 1 in 20 chance that the projections were right about CO2, what would they do? The case of the resigning editor and reviewers at the Remote Sensing journal was raised, by Andrew I think, as an example of something wrong with the science – if a weak paper gets through, why not simply print a rebuttal, why resign, and why, in particular, apologise to Trenberth – a man not in the speciality in question. Andrew raised the question as to whether peer review was adequate in climate science, and the politicised situation. I think there was consensus that peer review is not perfect and that moves to open peer review were a good development. Several people pointed out that both sides of the debate had been politicised.

The discussion had been, as they say, wide-ranging and often lively. But always temperate, and my impression was that everyone would have felt they had some opportunity to be heard. Dr Wilson helped keep an even keel, and invited us all to another room nearby for refreshments and further discussion. All in all, a worthwhile event with some good communication of perspectives and bits and pieces of ‘facts’. Would that such events, in such an open and courteous atmosphere, could be held far and wide. They weren’t in the past, and we were told by some that the debate was over. I think for most of us, it has in fact scarcely begun. Back to the car park to find some of the West Sands had been spread there by the wind to give a slightly Saharan look to the place."

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Reader Comments (365)

Those who propose a hypothesis have it to prove. Those who are not impressed by the proof have no onus to prove anything in response.

Apr 30, 2012 at 2:54 PM | Unregistered CommenterRhoda

FFS Rhoda, you cannot prove a hypothesis. You can only reject one based on the data. Your impressions are, sorry to say, entirely irrelevant.

Apr 30, 2012 at 2:55 PM | Unregistered Commentericer

The relevance of the cheats is that they should be disowned by honest scientists. Rob Wilson is aware of the inadequacy of Mann's work. He mentions it in the emails. He does not disown the work publicly, or any other of the examples of dishonest behaviour of which he is well aware. He could be right here saying why, or correcting me if I am wrong, except he went off in a huff for reasons I cannot divine.

Apr 30, 2012 at 2:58 PM | Unregistered CommenterRhoda

So you are saying that Rob WIlson is a cheat.

Apr 30, 2012 at 2:58 PM | Unregistered Commentericer

You are wrong. It is not my responsibility to disprove or reject any hypothesis. You are right to say it can only be falsified, but I have no need even to do that when the null hypothesis fits the data. Perhaps you are aware of any falsification criteria proposed by the AGW crew? Perhaps you can say what their null hypothesis is?

Apr 30, 2012 at 3:02 PM | Unregistered CommenterRhoda

No I am not saying Rob Wilson is a cheat. I do say that he appears to be aware of cheating and does not speak against it. He could be here defending that position or refuting it if he liked, but he is not.

Apr 30, 2012 at 3:04 PM | Unregistered CommenterRhoda

Yes, the null hypothesis is that the observational data showing climate change is inconsistent with CO2 induced global warming.

Apr 30, 2012 at 3:04 PM | Unregistered Commentericer

Rob is a scientist, so according to the principles of hypothetico deductive reasoning he would generate an independent dataset from Mann, and reconstruct climate change over the last 1000 years based on that data. That is how scientists would refute Mann's work. It is a pretty straightforward task.

Apr 30, 2012 at 3:06 PM | Unregistered Commentericer

If the methodology produces hockey-sticks from red noise, nobody needs to go any further in replication of the work. Mann would have to do it again properly. Wilson admits in the emails that he got hockey-sticks from random data. Well done Rob. Now will the IPCC stop using Mann's work?

Your null hypothesis is completely duff.

Apr 30, 2012 at 3:16 PM | Unregistered CommenterRhoda

No, that is not correct. Because if his data is wrong _and_ his methodology is wrong then the fact that he is using the wrong methodology could mean that what he is saying is actually true. You need multiple, independent reconstructions to be able to make any case. Taking data from one methodology, or methodology from one dataset will be inconclusive. Hypothetico deductive reasoning.
Sorry you don't like the null hypothesis. I'm sure it doesn't feel the same way about you.

Apr 30, 2012 at 3:21 PM | Unregistered Commentericer

Isn't this the same Dr Rob Wilson that signed the infamous Julia Slingo petition stating that

"We, members of the UK science community, have the utmost confidence in the observational evidence for global warming and the scientific basis for concluding that it is due primarily to human activities. The evidence and the science are deep and extensive. They come from decades of painstaking and meticulous research, by many thousands of scientists across the world who adhere to the highest levels of professional integrity. That research has been subject to peer review and publication, providing traceability of the evidence and support for the scientific method. The science of climate change draws on fundamental research from an increasing number of disciplines, many of which are represented here. As professional scientists, from students to senior professors, we uphold the findings of the IPCC Fourth Assessment Report, which concludes that Warming of the climate system is unequivocal and that Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations."

along with Richard Betts and Tamsin Edwards.

Perhaps Dr Wilson you could justify signing this petition when you were well aware that Mann's Hockey Sticks could be produced from noise -

Apr 30, 2012 at 3:25 PM | Unregistered CommenterMarion

Even I'm not falling for that farrago of crap.

Apr 30, 2012 at 3:28 PM | Unregistered CommenterRhoda

Well, if you are not prepared to try and understand the scientific method I'm not sure why you feel entitled to an opinion about climate change.

Apr 30, 2012 at 3:32 PM | Unregistered Commentericer

I understand the scientific method. I can also see a farrago of crap. I do not need to send it away for analysis.

Apr 30, 2012 at 3:35 PM | Unregistered CommenterRhoda

Perhaps it is a hypothesis you could prove.

Apr 30, 2012 at 3:37 PM | Unregistered Commentericer

I'll include it in my forthcoming paper on duck identification by walk and call.

Apr 30, 2012 at 3:44 PM | Unregistered CommenterRhoda

Yeah, I think a lot of journals now accept 'what I'm not falling for' instead of logic.

Apr 30, 2012 at 3:46 PM | Unregistered Commentericer

Wikipedia (which I usually distrust) gives a fair description of hypothetico deductive reasoning as well as its shortcomings.
Hypothetico deductive reasoning requires: a) data; b) a hypothetical explanation for that data; c) a consequence of that explanation and experimentation to see if that consequence actually occurs.
So far we have a wide range of more or less scary predictions as to what the consequences might be and no experiments to verify any of these consequences. (Tinkering with models is not experimenting.)
Note the 'data' bit. Reliable and accurate data are better. Cobbling together a bunch of half-baked ideas and calling it a hypothesis doesn't count. If it did then any idiot could claim a hypothesis and demand that the nul hypothesis is what he says it is.
Since the fact that climate changes continually and that anthropogenic input to this change has in the past always been marginal are about the only things in this argument that every scientist, activist, and sceptic can agree on, the nul hypothesis is that data and consequences continue to be consistent with natural variation.
It is up to the proposer of the hypothesis to provide empirical evidence (models are not empirical evidence) that this time it's different.

Apr 30, 2012 at 3:50 PM | Registered CommenterMike Jackson

Mike, does that include somebody using bad methodology and bad data and stumbling across the truth being somehow vindicated? I don't think so, but my troll does.

Apr 30, 2012 at 4:07 PM | Unregistered CommenterRhoda

The ends have been known to justify the means but as a general rule bad data+bad methodology will produce bad results.
Much safer to assume if you're using tree rings as temperature proxies (which the dendrochronologists tell us they aren't, and I reckon they should know) and apply "original" statistical methods which work equally well on whatever crap data you've fed into the calculation that the results will be ---- how shall I put this? ---- totally useless except as firelighters or chip wrappings.
Try it along with some hypothetico deductive reasoning sometime and see what drips out!

Apr 30, 2012 at 4:17 PM | Registered CommenterMike Jackson

My hypothesis that it's one of Dr Wilson's students has been confirmed.

Apr 30, 2012 at 4:20 PM | Unregistered CommenterSnap Rivet

Wrong! To be quite honest I have no interest in hockey sticks or dendrochronology, as in my view these disciplines constitute an almost insignificant amount to climate change research. In my humble and likely misguided opinion the big climate change stuff is in CTD's and lapse rates. That's why I genuinely don't understand why you people are always carrying on about hockey sticks and stuff. It all seems a bit decadent.

Apr 30, 2012 at 4:25 PM | Unregistered Commentericer

Ceramic Tile Distributors?
Crash Test Dummies?
Cheaper Than Dirt?

"That's why I genuinely don't understand why you people are always carrying on about hockey sticks and stuff."

If we told you, you wouldn't understand. You'll have to figger it out for yourself.

Apr 30, 2012 at 4:42 PM | Unregistered CommenterSnap Rivet

Apr 30, 2012 at 4:43 PM | Unregistered Commentericer


Cyber-Transmitted Disease

Apr 30, 2012 at 4:47 PM | Unregistered CommenterSnap Rivet

"Wrong! To be quite honest I have no interest in hockey sticks or dendrochronology, as in my view these disciplines constitute an almost insignificant amount to climate change research."

Icer, if you want to understand why so many lay people, as well as sensible scientists, are sceptical of AGW you will need to appreciate the malevolent political influence of Al Gore, and of the IPCC, whose third and fourth reports in particular relied so heavily on Mann's "hockey stick" (a trick, by the way, not a discipline) and on other dendrochronological nonsense.

Please take the time to read the "Summary for Policymakers" in those reports, then the book on the "hockey stick" written by our esteemed host. Then come back and tell us what you have learnt.

By the way, it's not necessary to write another paper to demonstrate that a paper is flawed, or in some way improperly presented (e.g. without providing access to the raw data upon which it is based); well argued - and properly referenced - blog posts are quite adequate, from whatever quarter they come.

Apr 30, 2012 at 4:48 PM | Unregistered CommenterCassio

Well, I'm sorry to upset you all about your precious hockey stick but I think if you all read a bit more widely you might find corroborating data regarding climate change that is not a tree.

Apr 30, 2012 at 4:51 PM | Unregistered Commentericer

"Well, I'm sorry to upset you all about your precious hockey stick but I think if you all read a bit more widely you might find corroborating data regarding climate change that is not a tree."

Sadly, Icer, it's clearly a waste of time exchanging views with you, as it was with Chris earlier on this thread. I can only hope that you will take the trouble to acquaint yourself with the most compelling reasons for scepticism about AGW (let alone CAGW), starting with previous threads on this blog, and on the estimable Climate Audit blog, and not forgetting the good Bishop's excellent demolition of Mann.

Apr 30, 2012 at 5:03 PM | Unregistered CommenterCassio

If you genuinely don't understand why we "carry on" about hockey sticks then you haven't been paying attention.
Mann did the one thing that was causing the warmist argument a problem: he "got rid of" the Mediaeval Warm Period. Without MBH98 — which included the notorious graph that was like manna from heaven to the IPCC judging by the number of times they used it — the late 20th century warming was nothing special. Not what they wanted to hear at all, that.
These temperatures were unprecedented. Never been anything like them ever, ever, ever. Catastrophe was about to descend on us. But salvation was at hand. The great Goddess, Gaia, would forgive us our sins if we truly repented.
Oh, and stopped using fossil fuels. Very convenient for those eco-warriors who have been arguing that to no avail for decades. Do forgive my cynicism!

Trouble is, icer, there is nothing unprecedented about late 20th century warming. It is consistent with a 30-year cycle which saw a warm then cool then warm again period in the 20th century overlaid by a multi-century pattern which has seen the LIttle Ice Age, the Mediaeval Warm Period, the Dark Ages, the Roman Warm Period.
The current 30-year period is coming to an end. I would expect to see at least a plateau, possibly a fall, for the next 30 years.
And on the basis of that consistency, which doesn't take a genius to see, the burden of proof does not lie with those of us say that natural variation can explain the present state of the climate but with those who claim that it can't — and not by dubious statistical methods, constantly adjusted temperature data (always in their favour, you'll notice), and the suppression or hand-waving dismissal of inconvenient facts.

Apr 30, 2012 at 5:04 PM | Registered CommenterMike Jackson

And what is the cause of the 30 year cycle? And why the increase over the last century if it is a 30 year cycle?

Apr 30, 2012 at 5:09 PM | Unregistered Commentericer

A CTD — an acronym for Conductivity, Temperature, and Depth — is the primary tool for determining essential physical properties of sea water.

An icer is something for adding ice when there isn’t enough of it, or as much as you’d like, or as much as you think there should be.

Apr 30, 2012 at 5:11 PM | Unregistered Commentergeoffchambers

In windows land CTD is crash to desktop. I withdraw my disingenuous or daft question. I omitted the possibility of both at once.

Apr 30, 2012 at 5:12 PM | Unregistered CommenterRhoda

Well done Geoff, you are about 10 posts behind.

Apr 30, 2012 at 5:12 PM | Unregistered Commentericer

So, can I just get this straight: This is a climate change website, and I have to explain to you how oceanic temperature profiles are measured? Or is this some kind of elaborate gag?

Apr 30, 2012 at 5:25 PM | Unregistered Commentericer

OK, it's a gag. Very funny. Cheers all.

Apr 30, 2012 at 5:28 PM | Unregistered Commentericer

No, in the case of the ocean, you only need to tell us how far back reliable measurements go if you want us to think something is happening on a centennial or millenial scale. And we need to teach you that when you introduce a three letter acronym in the absence of a glossary you tell the sudience what it is at least the first time otherwise you may suffer from misunderstandings, and we wouldn't want that.

Apr 30, 2012 at 5:38 PM | Unregistered CommenterRhoda

Can I get this straight - you are accusing most of the comments here of being ignorant, but you don't know who Steve McIntyre is? Or is this...

Apr 30, 2012 at 5:40 PM | Registered CommenterPaul Matthews

There is nothing honest about icer's presence here. Can we please stop filling up each other's emails with useless replies to his meaningless contributions.

Apr 30, 2012 at 5:44 PM | Registered Commenteromnologos

omnologos, just filling in time until Rob comes back to answer the many questions..

Apr 30, 2012 at 6:03 PM | Unregistered CommenterRhoda

And what is the cause of the 30 year cycle? And why the increase over the last century if it is a 30 year cycle?
Well done. Two fatuous questions in one post.
You may have noticed my use of the phrase "natural variation" which explains the 30-year cycle. You may also have noticed the phrase "overlaid by a multi-century pattern" which, since we are probably (I'll happily agree to possibly not but probably) still coming out if the Little Ice Age, accounts for the late 20th century warm period being warmer than the early 20th century warm period — though there is some doubt about the accuracy of some of the data and we are in any case talking about figures that are well within margins of error.
Of course, if you would like to give us the benefit of your wisdom and you have an explanation for the presence of 30-year cycles we'd be happy to listen.

I agree that icer is becoming a bit tedious but if your inbox is starting to overflow that's because you've asked for updates every time anyone squawks on here. The cure for that is in your own hands.

Apr 30, 2012 at 6:04 PM | Registered CommenterMike Jackson

Richard Betts,

"Palaoeclimate reconstructions are important to this second question as they indicate whether the warming is unusual or not, and hence whether the world has lived through these things before."

Aren't these reconstructions also rather vital to the validity of the climate models? I mean, if the recent warming isn't unusual, then something other than anthropogenic forcings must have created those previous warmings. Which would mean that anthropogenic forcings aren't the only show in town (which seems to be a basic assumption of the models).


Apr 30, 2012 at 6:06 PM | Unregistered CommenterJames Evans

"There is nothing honest about icer's presence here. Can we please stop filling up each other's emails with useless replies to his meaningless contributions."

You're quite right, omnologos, and thank you for the timely rap over the knuckles. How often have I observed interesting threads being derailed by trolls and shouted (if only to my screen) "Don't feed them", only to fall into the same time-wasting trap myself in an idle moment while waiting for a 'phone call.

Gosh, I supposed for several foolish moments that I might have contributed to Icer's (and chris's) understanding of why sceptics are sceptical, but I should have realised from earlier posts than neither was in the slightest bit interested in that topic. Too bad. May they wallow in their foolish ignorance.

Much more disappointing for me was - once again - not to receive a response from Dr Betts after I had posed a question or two arising from his own posts on the same thread. Oversight ? Perhaps - he must be a busy man. Reluctance to engage with an obvious nutter or obsessive ? I think not (you can see that I do not use green ink). Unwillingness to clarify and/or defend the points that he has made on this blog ? I fear so.

Hey ho. Regrettably Dr Betts, like Dr Watson - who so spectacularly blotted his copybook on this thread (shades of David Cameron at the mo') - is enmeshed in AGW, on which he depends for a living. He wants friendly dialogue but cannot bring himsef to acknowledge what he surely knows to be true, that climatology is riddled with dishonesty and incompetence (cue our host's excellent book).

Dr Betts wrote on this thread that he tries not to tell people what to do; but unfortunately that does not prevent his employers at the Met Office, and the IPCC with which it entertains such cordial relations, from "bigging up" his research on "Impacts" to that end.

Incidentally it seems extraordinary that the Met Office employs researchers like Dr Betts, whose areas of interest and expertise are so far removed from actually forecasting the weather. Dr Betts and many of his colleagues would be better employed in universities, and the the grotesquely obese Met Office should return to its roots.

Apr 30, 2012 at 6:21 PM | Unregistered CommenterCassio


But anthropogenic forcing isn't the only show in town. Other forcings go into the models, and the indications (comparing model runs with and without the anthropogenic forcings) are that anthropogenic forcings are required to explain warming during the past few decades, but they aren't (as you correctly suggest) required to explain previous warming episodes. Robust paleoclimate reconstructions help to validate the model runs.

Of course, I'm not sure if Richard would give the same reply!



Apr 30, 2012 at 6:24 PM | Unregistered CommenterPaul Butler

Mike Jackson - your suggestion is not wise. It would mean for me to give up on reading interesting comments in the future by many people only because a cretin pops around. I'm just asking not to waste anybody's time.

Apr 30, 2012 at 6:35 PM | Registered Commenteromnologos

Dear All,
I have never publicly made a response w.r.t my very minor part in the ClimateGate e-mails. It is interesting to see how the whole thing blew up when most commentators (all?) did not have the whole story.

I do not want to comment about other e-mails, but I can say definitively that all of mine were single e-mails which were often part of a longer e-mail discussion thread – without that thread, they have all been taken out of context somewhat.

For example: The random data and a hockey stick reconstruction.
Steve Macintyre had spent much time showing that PCA could mine hockey stick shapes from random data. At the time, I did not believe that was possible, so I set up a simple experiment and if one generated enough random series (I think I worked with 1000), then it is entirely possible to get a calibration to northern hemisphere temperatures (or NAO or ENSO indices for that matter) by chance alone. However, you need lots of random series to get away with this. The reality of course, is that we are not working with random data – i.e. they are proxies of past climate. However, the exercise does highlight the “danger” of empirically screening data for reconstruction purposes.

One last comment w.r.t. Mann et al. (1998/99).
Is this analysis flawed? No, not really - it was one of the first attempts at trying to do a rather complicated job - but the results need to be cautiously taken in light of the methodological choices that Mann made. I do not agree with his PCregression approach, but I doubt he would now either. I do not agree that he included hydroclimate proxies in his data-set. I do not agree that he used tree-ring chronologies where periods were replicated by only one tree. I do not agree with the use of tree-ring chronologies that had not been processed to capture centennial scale variability.
So my response to Mann’s work was to do my own iterations of large scale temperature reconstructions - specifically the following papers:

D'Arrigo, R., Wilson, R. and Jacoby, G. 2006. On the long-term context for late 20th century warming. (Journal of Geophysical Research, Vol. 111, D03103, doi:10.1029/2005JD006352

Wilson, R., Tudhope, A., Brohan, P., Briffa, K., Osborn, T. and Tett, S. 2006. 250-years of reconstructed and modeled tropical temperatures. Journal of Geophysical Research. 111, C10007, doi:10.1029/2005JC003188

Wilson, R., D’Arrigo. R., Buckley, B., Büntgen, U., Esper, J., Frank, D., Luckman, B., Payette, S. Vose, R. and Youngblut, D. 2007. A matter of divergence – tracking recent warming at hemispheric scales using tree-ring data. JGR - Atmospheres. VOL. 112, D17103, doi:10.1029/2006JD008318

I am sure improved iterations will be developed over the coming years. I am also sure that other palaeoclimate scientists will also have their own criticisms of my techniques and approaches. That is science and I welcome the debate.

Unfortunately, what occurs on this blog – MOSTLY – is not science. I see only ranting and angry people. I am truly sorry if I antagonised and annoyed many of you. I have told Andrew that I will try and find time to write a couple of guest posts on some of the issues he has raised.

Finally, for those of you who do not trust tree-rings, a really interesting paper that may be of interest is:

Ljungqvist FC, Krusic PJ, Brattstrom G, Sundqvist HS (2012) Northern Hemisphere temperature patterns in the last 12 centuries. Climate Past 8: 227-249. doi: 10.5194/cp-8-227-2012

It is freely avaible.


Apr 30, 2012 at 6:53 PM | Unregistered CommenterRob Wilson (aka The Yummy Troll)

Paul, if we cannot agree on the timing or scale of previous episodes of warming how can we know what forcings were acting then which are not acting now? What is the definitive temperature record which we can use for calibration? Does it have the global MWP, for example, or not?

Apr 30, 2012 at 6:58 PM | Unregistered CommenterRhoda

Paul Butler,

Thanks for the reply.

My understanding (correct me when I'm wrong) is that the Met Office model contains the following forcings:

Solar variability (a tiny effect)
Volcanic erruptions (a short-term downward push on temps)

What previous warming events do the models explain? And what forcings do the models use to explain them?


Apr 30, 2012 at 7:00 PM | Unregistered CommenterJames Evans

Rhoda, Icer

Enough thanks. You can continue on the discussion forum if you like.

Apr 30, 2012 at 7:21 PM | Registered CommenterBishop Hill

Rob Wilson,

"I am truly sorry if I antagonised and annoyed many of you."

Fair enough.

"Unfortunately, what occurs on this blog – MOSTLY – is not science."

I don't think any of it is science. It's chat - amongst a bunch of people who are really, really interested in the science. Things can get a bit heated, but a good argument will surely win the day, don't you think? And by "a good argument" I don't mean a sophisticated debating technique. I mean that "the truth will out". Is that the saying?

Anyway, thanks for clearing the air.

Apr 30, 2012 at 7:26 PM | Unregistered CommenterJames Evans

[Rob Wilson]: "One last comment w.r.t. Mann et al. (1998/99).
Is this analysis flawed? No, not really - it was one of the first attempts at trying to do a rather complicated job - but the results need to be cautiously taken in light of the methodological choices that Mann made...."

Rob, thank you for your further comments and willingness to explain. I am one who does not pretend to engage in the "scientific" debates per se.... I am not a scientist, but I am much interested in the public policy aspects of what [some] scientists and activists tell us are dire and catastrophic threats to our world as we know it.

While I can understand your description of Mann et al (1998/99) as a tentative, exploratory foray into complex matters, that is not AT ALL how Mann's work was presented to the wider world..... Mann and some of his co-authors did not do all of the trumpeting and glorifying of the "hockey stick" etc. as some decisive moment in the policy debates, but they certainly have contributed to the spirit of "the science is settled" wrt to massive policy proposals that go far far beyond any settled science.

Part of the furor in these debates, I think, is that everyone concerned with "catastrophes" (both scientists and non-scientists) does a lot of blending and mixing of different areas of the debates.

I do know very well how the "hockey stick" graphs and related claims have been widely utilized to try to bludgeon millions of citizens and countless policy makers across many (all) countries to accept "catastrophic" threats as a justification for some of the most massive govt. interventions proposed in human history. THAT is where it is no longer only about the science per se. Mann et al became the hardened tip of a spear used as a public policy weapon against all who might question anything about extreme scenarios. That process explains much anger and resistance from people who perceive many mis-uses of the "science" for vast public policy agendas.

Your welcome caveats about Mann's analysis do help to indicate how tentative (at best) the whole "hockey stick" graph was even for people of Mann's persuasion. Yet, that graph has been widely trumpeted without the caveats and is widely known as the most iconic part of the whole C-AGW debate (well after polar bears on ice floes I suppose).

So I think it is great that you are pursuing the kinds of research you are doing, but when you pause to think about wider issues of "science and society" you and others scientists need to realize that the various public bodies are being bludgeoned with the "hockey stick" and imperiled polar bears.

Apr 30, 2012 at 8:12 PM | Unregistered CommenterSkiphil

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